Hemodynamic and autonomic dysfunction in symptomatic carotid artery stenosis

Hemodynamic failure in patients with steno-occlusive arterial disease is a major risk factor for stroke. Previous studies have identified impaired autonomic function in patients with carotid artery stenosis. Our study explores autonomic dysfunction and altered cerebrovascular hemodynamics in patients with stenosis and suspected hemodynamic failure.

To assess autonomic nervous system dysfunction, patients underwent heart rate variability (HRV) testing, an active stand test, and the Valsalva maneuver with simultaneous monitoring of heart rate, blood pressure, and cardiac output. Transcranial Doppler was used to measure relative changes in cerebral blood flow during Valsalva.

Analysis of 13 patients and 19 controls revealed a significantly greater decrease in cerebral blood flow in the patient group during Valsalva, as evidenced by mean relative changes in time-averaged peak velocities ±SE of 0.80 ± 0.04 in patients compared to 0.96 ± 0.05 in controls (p < 0.05). There were no significant differences in mean arterial blood pressure or heart rate during the Valsalva maneuver. HRV analysis and the active stand test did not reveal autonomic dysfunction or orthostatic intolerance.

Patients with steno-occlusive carotid artery disease exhibit impaired intracranial flow during Valsalva-induced blood pressure reduction. However, our results do not support the presence of significant autonomic dysfunction in patients with symptomatic large-vessel cerebrovascular disease as measured by HRV and blood pressure reduction during active stand.